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Folic Acid in Pregnancy Shown To Reduce Autism Risk


Prenatal folic acid supplements appear to reduce the risk for autistic spectrum disorders, according to a new study published today in the Journal of the American Medical Association (JAMA).

Taking folic acid supplements during early pregnancy had already been known to protect against spina bifida and other neural tube defects in children.

But this latest study of 85,176 babies in Norway found that mothers who took folic acid supplements in early pregnancy had a 39 percent reduced risk of having children with autistic disorder compared with mothers who did not take folic acid.

Plus: Folic Acid: Why It's Important

However, the window of time in which mothers need to take the folic acid appears to be as narrow as it is critical. Her child’s risk of autism was reduced only when the supplements were taken between 4 weeks before to 8 weeks after the start of pregnancy.

“We examined the rate of autism spectrum disorders in children born to mothers who did or did not take folic acid during pregnancy. There was a dramatic reduction in the risk of autistic disorder in children born to mothers who took folic acid supplements,” says Pål Surén, first author and epidemiologist at the Norwegian Institute of Public Health (NIPH).

The Centers for Disease Control and Prevention estimate that about 1 in 88 children in the U.S. have been identified with an Autism Spectrum Disorder (ASD).

"This is an actionable and relatively inexpensive item," Alycia Halladay, senior director of environmental and clinical sciences at Autism Speaks tells "Women who are concerned about the risk in their children should take folic acid as soon as they can before becoming pregnant, as it may reduce the risk of autism in their child."

Plus: How Much Folic Acid Should You Take?

Of course, Halladay is quick to stress that folic acid will not prevent autism; it will merely lower the risk. She also stresses that women who have not taken folic acid need not feel guilty. 

"We don't want women coming away from reading this saying 'there is something I could have done that I didn't do'," she adds. 

Autism Spectrum Disorders are amongst the most hereditary of mental disorders, but little is known about how the disorder develops. Consequently, methods for diagnosis, prevention, and treatment are limited.

Folic acid (Vitamin B9) is required for DNA synthesis and repair in the human body, and its naturally occurring form – folate – is found in leafy vegetables, peas, lentils, beans, eggs, yeast, and liver.